Many studies have shown the poor suffer more injuries and deaths from crashes than do wealthier residents of a city. A new study suggests that the major reason is that poor people are simply exposed to more traffic and more complex intersections in their neighborhoods.

The study, in the American Journal of Public Health, examined crash injuries at intersections in Montreal. Intersections in poorer neighborhoods saw 3.9 times more cyclist crash injuries than in the richest neighborhoods. For motor vehicle occupants, the rate was for 4.3 higher; for pedestrians it was 6.3 higher.

Mean traffic volume at intersections in the poorest neighborhoods was 2.4 times higher than in the wealthiest neighborhoods. The poorest neighborhoods also had more intersections with arterials and a higher proportion of four-way (as opposed to three-way) intersections. And, relevant to pedestrian and cyclist injuries, a greater number residents in poorer neighborhoods used more vulnerable, non-auto modes to get to work.

In several multivariate regressions, when the traffic exposure and roadway geometry variables are included as controls, differences in predicted injury rates between poor and rich neighborhoods greatly diminish.

The authors conclude that “poverty per se does not produce [crash injuries]—exposure to moving vehicles does.”

Eric Sundquist is Managing Director at SSTI. He can be reached at Erics@ssti.us.